I would say the contact with support should be made by the hotmail subscriber. They can claim they don't receive their important mail and want that situation rectified. They have a customer relation with hotmail. My experience is that contacting services where you are not a customer yourself is usually very difficult and will often not result in any action. Another problem is that hotmail uses a cache for SPF and DMARC and it takes very long to expire. I have seen mail problems in hotmail at least a month after an SPF record was changed to include more valid addresses, and they were still considered invalid (resulting in postmaster report via DMARC info). Rob